Plus or minus

Plus bikes promise more grip and a smoother ride… and another hefty credit card bill. But what if there was a cheaper way to go Plus?

>>> Click here to find the best plus bikes

Check your frame

If you’ve got a 29er then converting to Plus is relatively easy, and although the latest Boost hub widths offer benefits, they’re not essential — we converted a Specialized Camber Evo 29er.

Our test mule swallowed the 2.8in WTB Trailblazer tyres happily, and we’ve ridden it in the mud without any clogging problems. Just watch out for chain clearance if you’re running a front mech. Our standard 29er Pike fork also offered ample clearance.

Choose a wheel

The most affordable wheelset is Specialized’s Roval Traverse at £400, but with just 29mm internal width (40mm is common with Plus) they’re rather narrow. Syncros makes the TR1.5 Plus wheelset for £650, but the hubs are 110/148mm Boost, so won’t fit many existing frames.

Which leaves building your own wheels, as we did. We used DT Swiss’s new XM551 rim, which has an ample 40mm internal width, and is one of the cheaper options too, at £90 a rim. These were built up on Hope hubs and fitted with tubeless rim strips. The resulting wheels weighed 1,112g (r) and 1,004g (f).

Find a tyre

Tyre options are more limited. For maximum clearance, we decided to run 2.8in tyres rather than 3.0in. Options include Schwalbe’s Nobby Nic and Rocket Ron, Maxxis’s Ikon and Recon, and the WTB Trailblazer. The WTB also happens to be a Plus size bargain at £39.99. It has a 70mm-wide carcass (2.75in) and a 60mm tread (2.36in), weighs 900g and works well in firmer, drier conditions. Not so good when it’s wet or slippery…

Camber conversion clearance

Put it all together

While 27.5 Plus and 29in are close in diameter, they are not the same. Our 27.5 Plus wheels and tyres had a 20mm smaller outside diameter measurement (725mm) than the 29in wheels with 2.3in tyres we took off.

Consequently, the bottom bracket height on our Camber dropped 10mm, dipping just under 320mm. That may be too low for some. On the other hand, if you have a 29er with a lofty bottom bracket, converting to Plus may actually be a blessing.

Watch: Scott launches its plus size genius

What to expect

If pedal strikes become a problem, try running shorter 170mm cranks. Or, if your bike has a BB30 bottom bracket, Wheels Manufacturing ( sells an eccentric BB that can be used to raise or lower your BB by +/- 7mm without otherwise affecting the geometry.

The bike may feel a bit bouncy with the new wheels and tyres; our Camber definitely has a livelier feel — we fitted tubes for added sidewall protection and ran 15/16psi front and rear. Trails also seem smoother, impossible climbs are now achievable and rolling pace hasn’t taken a hit. Its nemesis, so far, is mud and slippery terrain.